Improvement in escapements for time-pieces



S. W. ROBINSON.

Clock Escapement.

No. 59,658. Patented Nov. 13, 1866 UNITED STATES PATENT OFFICE.

S. ROBINSON, OF DETROIT, MICHIGAN,

IMPROVEMENT IN ESCAPEMENTS FOR TIME-PIECES Specification forming partofLetters Patent No. 59,658, dated November 13, 1866.

To all whom it may concern:

Be it known that I, S. W. ROBINSON, of Detroit, in the county of IVayneand State of Michigan, have invented a new and Improved Eseapement forTime-Pieces 5 and I do hereby declare that the following is a full,clear, and exact description thereof, which will enable others skilledin the art to make and use the same, reference being had to theaccompanying drawings, forming part of this specification, in which-Figure 1 represents a plan or top view of this invention. Fig. 2 is alongitudinal vertical section of the same.

Similar letters of reference indicate like parts.

The object of this invention is to impart to the balance impulses whichshall be equal to each other in the amount of force, a single impulsebeing given at each double vibration of the balance. This purpose isetfected by a lever acted upon by a spring, and applied, in combinationwith the escape-wheel, the balance, and two detents, in such a mannerthat the force required for unlocking the detents is derived entirelyfrom the hair-springs of the balance and lever, while the power of thehairspring, acting on the lever, imparts to the bal ance the desiredimpulse at eachdouble vibra tion of said balance.

A designates the escape-wheel, which acts against its detent J with aforce communicated to it through the train of wheels from the mainspringor weight. The detent J is composed of a thin spring, or otherwise, witha small hook at its end, and it is secured in such a position that thehook catches against one of the teeth of the escape-wheel and retainsthe same, unless released by the action of the lever B or by some othercause. Said lever has its fulcrum on an arbor, a, and said arborconnects with a hair-spring, H, which causes the lever B to bear on itsdetent I, as clearly shown in Fig. 1, with a force proportionate to theforce of the hair-spring. This latter detent is so constructed as tobecome unlocked from the lever by a small projection, E, upon the axisof the balance-wheel O. This projection should be so placed that thelever is unlocked at the proper instant to strike the pallet D of thebalance; and in order to enable said lever to act on the pallet, andalso on the detent 1, its end is fork-shaped, or otherwise soconstructed that it has two bearing-points, one of which acts on thedetent, and the other at the proper moment on the pallet.

The impulse thus imparted to the balance is given entirely by thehair-spring H, which acts on the arbor a of thelever B. When the leverhas passed a sufiicientdistance to clear the pallet of the balance, itcontinues its motion for a very short space, until its opposite endunlocks the detent J from the escapewheel, which immediatel y uponbeingdetached from said detent acts by one of its teeth on the lever B,and relocks the same on its detent I. As soon as this is accomplishedthe tooth of the escape-wheel passes off of the end of the lever B, andanother toot-h strikes and is held by the detent J. But an instant isrequired to put the lever back to its original position, and themechanism is in readiness to impart another impulse to the balance.

The impulses are thus all given by the hairspring H, and they can varyperceptibly only by the variations of the temperature. The error causedthereby can be easily compensated for on the balance 0. The impulses areentirely independent of the inequalities"and imperfections which mayexist in the wheelwork, and the necessity of a barrel and fusee in nicechronometers is avoided, and it isonly necessary to jewel the holes forthe balancepivots, the lever-pivots, and the pivots of the detent I.

What I claim as new, and desire to secure by Letters Patent, is

The lever B and hair-spring H, in combination with the detents I J,escape-wheel A, and balance G, constructed and opera-ting substantiallyas and for the purpose described.

S. V. ROBINSON.

Witnesses J ULIUS SroLL, CARL GEHRNEMANN.

